/*
  PubSubClient.cpp - A simple client for MQTT.
  Nick O'Leary
  http://knolleary.net
*/

#include "psc.h"
#include "Arduino.h"

PubSubClient::PubSubClient()
{
	this->_state = MQTT_DISCONNECTED;
	this->_client = NULL;
	this->stream = NULL;
	setCallback(NULL);
}

PubSubClient::PubSubClient(Client &client)
{
	this->_state = MQTT_DISCONNECTED;
	setClient(client);
	this->stream = NULL;
}

PubSubClient::PubSubClient(IPAddress addr, uint16_t port, Client &client)
{
	this->_state = MQTT_DISCONNECTED;
	setServer(addr, port);
	setClient(client);
	this->stream = NULL;
}
PubSubClient::PubSubClient(IPAddress addr, uint16_t port, Client &client, Stream &stream)
{
	this->_state = MQTT_DISCONNECTED;
	setServer(addr, port);
	setClient(client);
	setStream(stream);
}
PubSubClient::PubSubClient(IPAddress addr, uint16_t port, MQTT_CALLBACK_SIGNATURE, Client &client)
{
	this->_state = MQTT_DISCONNECTED;
	setServer(addr, port);
	setCallback(callback);
	setClient(client);
	this->stream = NULL;
}
PubSubClient::PubSubClient(IPAddress addr, uint16_t port, MQTT_CALLBACK_SIGNATURE, Client &client, Stream &stream)
{
	this->_state = MQTT_DISCONNECTED;
	setServer(addr, port);
	setCallback(callback);
	setClient(client);
	setStream(stream);
}

PubSubClient::PubSubClient(uint8_t *ip, uint16_t port, Client &client)
{
	this->_state = MQTT_DISCONNECTED;
	setServer(ip, port);
	setClient(client);
	this->stream = NULL;
}
PubSubClient::PubSubClient(uint8_t *ip, uint16_t port, Client &client, Stream &stream)
{
	this->_state = MQTT_DISCONNECTED;
	setServer(ip, port);
	setClient(client);
	setStream(stream);
}
PubSubClient::PubSubClient(uint8_t *ip, uint16_t port, MQTT_CALLBACK_SIGNATURE, Client &client)
{
	this->_state = MQTT_DISCONNECTED;
	setServer(ip, port);
	setCallback(callback);
	setClient(client);
	this->stream = NULL;
}
PubSubClient::PubSubClient(uint8_t *ip, uint16_t port, MQTT_CALLBACK_SIGNATURE, Client &client, Stream &stream)
{
	this->_state = MQTT_DISCONNECTED;
	setServer(ip, port);
	setCallback(callback);
	setClient(client);
	setStream(stream);
}

PubSubClient::PubSubClient(const char *domain, uint16_t port, Client &client)
{
	this->_state = MQTT_DISCONNECTED;
	setServer(domain, port);
	setClient(client);
	this->stream = NULL;
}
PubSubClient::PubSubClient(const char *domain, uint16_t port, Client &client, Stream &stream)
{
	this->_state = MQTT_DISCONNECTED;
	setServer(domain, port);
	setClient(client);
	setStream(stream);
}
PubSubClient::PubSubClient(const char *domain, uint16_t port, MQTT_CALLBACK_SIGNATURE, Client &client)
{
	this->_state = MQTT_DISCONNECTED;
	setServer(domain, port);
	setCallback(callback);
	setClient(client);
	this->stream = NULL;
}
PubSubClient::PubSubClient(const char *domain, uint16_t port, MQTT_CALLBACK_SIGNATURE, Client &client, Stream &stream)
{
	this->_state = MQTT_DISCONNECTED;
	setServer(domain, port);
	setCallback(callback);
	setClient(client);
	setStream(stream);
}

boolean PubSubClient::connect(const char *id)
{
	return connect(id, NULL, NULL, 0, 0, 0, 0, 1);
}

boolean PubSubClient::connect(const char *id, const char *user, const char *pass)
{
	return connect(id, user, pass, 0, 0, 0, 0, 1);
}

boolean PubSubClient::connect(const char *id, const char *willTopic, uint8_t willQos, boolean willRetain, const char *willMessage)
{
	return connect(id, NULL, NULL, willTopic, willQos, willRetain, willMessage, 1);
}

boolean PubSubClient::connect(const char *id, const char *user, const char *pass, const char *willTopic, uint8_t willQos, boolean willRetain, const char *willMessage)
{
	return connect(id, user, pass, willTopic, willQos, willRetain, willMessage, 1);
}

boolean PubSubClient::connect(const char *id, const char *user, const char *pass, const char *willTopic, uint8_t willQos, boolean willRetain, const char *willMessage, boolean cleanSession)
{
	if (!connected())
	{
		int result = 0;

		if (domain != NULL)
		{
			result = _client->connect(this->domain, this->port);
		}
		else
		{
			result = _client->connect(this->ip, this->port);
		}
		if (result == 1)
		{
			nextMsgId = 1;
			// Leave room in the buffer for header and variable length field
			uint16_t length = MQTT_MAX_HEADER_SIZE;
			unsigned int j;

#if MQTT_VERSION == MQTT_VERSION_3_1
			uint8_t d[9] = {0x00, 0x06, 'M', 'Q', 'I', 's', 'd', 'p', MQTT_VERSION};
#define MQTT_HEADER_VERSION_LENGTH 9
#elif MQTT_VERSION == MQTT_VERSION_3_1_1
			uint8_t d[7] = {0x00, 0x04, 'M', 'Q', 'T', 'T', MQTT_VERSION};
#define MQTT_HEADER_VERSION_LENGTH 7
#endif
			for (j = 0; j < MQTT_HEADER_VERSION_LENGTH; j++)
			{
				buffer[length++] = d[j];
			}

			uint8_t v;
			if (willTopic)
			{
				v = 0x04 | (willQos << 3) | (willRetain << 5);
			}
			else
			{
				v = 0x00;
			}
			if (cleanSession)
			{
				v = v | 0x02;
			}

			if (user != NULL)
			{
				v = v | 0x80;

				if (pass != NULL)
				{
					v = v | (0x80 >> 1);
				}
			}

			buffer[length++] = v;

			buffer[length++] = ((MQTT_KEEPALIVE) >> 8);
			buffer[length++] = ((MQTT_KEEPALIVE)&0xFF);

			CHECK_STRING_LENGTH(length, id)
			length = writeString(id, buffer, length);
			if (willTopic)
			{
				CHECK_STRING_LENGTH(length, willTopic)
				length = writeString(willTopic, buffer, length);
				CHECK_STRING_LENGTH(length, willMessage)
				length = writeString(willMessage, buffer, length);
			}

			if (user != NULL)
			{
				CHECK_STRING_LENGTH(length, user)
				length = writeString(user, buffer, length);
				if (pass != NULL)
				{
					CHECK_STRING_LENGTH(length, pass)
					length = writeString(pass, buffer, length);
				}
			}

			write(MQTTCONNECT, buffer, length - MQTT_MAX_HEADER_SIZE);

			lastInActivity = lastOutActivity = millis();

			while (!_client->available())
			{
				unsigned long t = millis();
				if (t - lastInActivity >= ((int32_t)MQTT_SOCKET_TIMEOUT * 1000UL))
				{
					_state = MQTT_CONNECTION_TIMEOUT;
					_client->stop();
					return false;
				}
			}
			uint8_t llen;
			uint16_t len = readPacket(&llen);

			if (len == 4)
			{
				if (buffer[3] == 0)
				{
					lastInActivity = millis();
					pingOutstanding = false;
					_state = MQTT_CONNECTED;
					return true;
				}
				else
				{
					_state = buffer[3];
				}
			}
			_client->stop();
		}
		else
		{
			_state = MQTT_CONNECT_FAILED;
		}
		return false;
	}
	return true;
}

// reads a byte into result
boolean PubSubClient::readByte(uint8_t *result)
{
	uint32_t previousMillis = millis();
	while (!_client->available())
	{
		yield();
		uint32_t currentMillis = millis();
		if (currentMillis - previousMillis >= ((int32_t)MQTT_SOCKET_TIMEOUT * 1000))
		{
			return false;
		}
	}
	*result = _client->read();
	return true;
}

// reads a byte into result[*index] and increments index
boolean PubSubClient::readByte(uint8_t *result, uint16_t *index)
{
	uint16_t current_index = *index;
	uint8_t *write_address = &(result[current_index]);
	if (readByte(write_address))
	{
		*index = current_index + 1;
		return true;
	}
	return false;
}

uint16_t PubSubClient::readPacket(uint8_t *lengthLength)
{
	uint16_t len = 0;
	if (!readByte(buffer, &len))
		return 0;
	bool isPublish = (buffer[0] & 0xF0) == MQTTPUBLISH;
	uint32_t multiplier = 1;
	uint16_t length = 0;
	uint8_t digit = 0;
	uint16_t skip = 0;
	uint8_t start = 0;

	do
	{
		if (len == 5)
		{
			// Invalid remaining length encoding - kill the connection
			_state = MQTT_DISCONNECTED;
			_client->stop();
			return 0;
		}
		if (!readByte(&digit))
			return 0;
		buffer[len++] = digit;
		length += (digit & 127) * multiplier;
		multiplier *= 128;
	} while ((digit & 128) != 0);
	*lengthLength = len - 1;

	if (isPublish)
	{
		// Read in topic length to calculate bytes to skip over for Stream writing
		if (!readByte(buffer, &len))
			return 0;
		if (!readByte(buffer, &len))
			return 0;
		skip = (buffer[*lengthLength + 1] << 8) + buffer[*lengthLength + 2];
		start = 2;
		if (buffer[0] & MQTTQOS1)
		{
			// skip message id
			skip += 2;
		}
	}

	for (uint16_t i = start; i < length; i++)
	{
		if (!readByte(&digit))
			return 0;
		if (this->stream)
		{
			if (isPublish && len - *lengthLength - 2 > skip)
			{
				this->stream->write(digit);
			}
		}
		if (len < MQTT_MAX_PACKET_SIZE)
		{
			buffer[len] = digit;
		}
		len++;
	}

	if (!this->stream && len > MQTT_MAX_PACKET_SIZE)
	{
		len = 0; // This will cause the packet to be ignored.
	}

	return len;
}

boolean PubSubClient::loop()
{
	if (connected())
	{
		unsigned long t = millis();
		if ((t - lastInActivity > MQTT_KEEPALIVE * 1000UL) || (t - lastOutActivity > MQTT_KEEPALIVE * 1000UL))
		{
			if (pingOutstanding)
			{
				this->_state = MQTT_CONNECTION_TIMEOUT;
				_client->stop();
				return false;
			}
			else
			{
				buffer[0] = MQTTPINGREQ;
				buffer[1] = 0;
				_client->write(buffer, 2);
				lastOutActivity = t;
				lastInActivity = t;
				pingOutstanding = true;
			}
		}
		if (_client->available())
		{
			uint8_t llen;
			uint16_t len = readPacket(&llen);
			uint16_t msgId = 0;
			uint8_t *payload;
			if (len > 0)
			{
				lastInActivity = t;
				uint8_t type = buffer[0] & 0xF0;
				if (type == MQTTPUBLISH)
				{
					if (callback)
					{
						uint16_t tl = (buffer[llen + 1] << 8) + buffer[llen + 2]; /* topic length in bytes */
						memmove(buffer + llen + 2, buffer + llen + 3, tl);		  /* move topic inside buffer 1 byte to front */
						buffer[llen + 2 + tl] = 0;								  /* end the topic as a 'C' string with \x00 */
						char *topic = (char *)buffer + llen + 2;
						// msgId only present for QOS>0
						if ((buffer[0] & 0x06) == MQTTQOS1)
						{
							msgId = (buffer[llen + 3 + tl] << 8) + buffer[llen + 3 + tl + 1];
							payload = buffer + llen + 3 + tl + 2;
							callback(topic, payload, len - llen - 3 - tl - 2);

							buffer[0] = MQTTPUBACK;
							buffer[1] = 2;
							buffer[2] = (msgId >> 8);
							buffer[3] = (msgId & 0xFF);
							_client->write(buffer, 4);
							lastOutActivity = t;
						}
						else
						{
							payload = buffer + llen + 3 + tl;
							callback(topic, payload, len - llen - 3 - tl);
						}
					}
				}
				else if (type == MQTTPINGREQ)
				{
					buffer[0] = MQTTPINGRESP;
					buffer[1] = 0;
					_client->write(buffer, 2);
				}
				else if (type == MQTTPINGRESP)
				{
					pingOutstanding = false;
				}
			}
			else if (!connected())
			{
				// readPacket has closed the connection
				return false;
			}
		}
		return true;
	}
	return false;
}

boolean PubSubClient::publish(const char *topic, const char *payload)
{
	return publish(topic, (const uint8_t *)payload, strlen(payload), false);
}

boolean PubSubClient::publish(const char *topic, const char *payload, boolean retained)
{
	return publish(topic, (const uint8_t *)payload, strlen(payload), retained);
}

boolean PubSubClient::publish(const char *topic, const uint8_t *payload, unsigned int plength)
{
	return publish(topic, payload, plength, false);
}

boolean PubSubClient::publish(const char *topic, const uint8_t *payload, unsigned int plength, boolean retained)
{
	if (connected())
	{
		if (MQTT_MAX_PACKET_SIZE < MQTT_MAX_HEADER_SIZE + 2 + strlen(topic) + plength)
		{
			// Too long
			return false;
		}
		// Leave room in the buffer for header and variable length field
		uint16_t length = MQTT_MAX_HEADER_SIZE;
		length = writeString(topic, buffer, length);
		uint16_t i;
		for (i = 0; i < plength; i++)
		{
			buffer[length++] = payload[i];
		}
		uint8_t header = MQTTPUBLISH;
		if (retained)
		{
			header |= 1;
		}
		return write(header, buffer, length - MQTT_MAX_HEADER_SIZE);
	}
	return false;
}

boolean PubSubClient::publish_P(const char *topic, const char *payload, boolean retained)
{
	return publish_P(topic, (const uint8_t *)payload, strlen(payload), retained);
}

boolean PubSubClient::publish_P(const char *topic, const uint8_t *payload, unsigned int plength, boolean retained)
{
	uint8_t llen = 0;
	uint8_t digit;
	unsigned int rc = 0;
	uint16_t tlen;
	unsigned int pos = 0;
	unsigned int i;
	uint8_t header;
	unsigned int len;

	if (!connected())
	{
		return false;
	}

	tlen = strlen(topic);

	header = MQTTPUBLISH;
	if (retained)
	{
		header |= 1;
	}
	buffer[pos++] = header;
	len = plength + 2 + tlen;
	do
	{
		digit = len % 128;
		len = len / 128;
		if (len > 0)
		{
			digit |= 0x80;
		}
		buffer[pos++] = digit;
		llen++;
	} while (len > 0);

	pos = writeString(topic, buffer, pos);

	rc += _client->write(buffer, pos);

	for (i = 0; i < plength; i++)
	{
		rc += _client->write((char)pgm_read_byte_near(payload + i));
	}

	lastOutActivity = millis();

	return rc == tlen + 4 + plength;
}

boolean PubSubClient::beginPublish(const char *topic, unsigned int plength, boolean retained)
{
	if (connected())
	{
		// Send the header and variable length field
		uint16_t length = MQTT_MAX_HEADER_SIZE;
		length = writeString(topic, buffer, length);
		uint16_t i;
		uint8_t header = MQTTPUBLISH;
		if (retained)
		{
			header |= 1;
		}
		size_t hlen = buildHeader(header, buffer, plength + length - MQTT_MAX_HEADER_SIZE);
		uint16_t rc = _client->write(buffer + (MQTT_MAX_HEADER_SIZE - hlen), length - (MQTT_MAX_HEADER_SIZE - hlen));
		lastOutActivity = millis();
		return (rc == (length - (MQTT_MAX_HEADER_SIZE - hlen)));
	}
	return false;
}

int PubSubClient::endPublish()
{
	return 1;
}

size_t PubSubClient::write(uint8_t data)
{
	lastOutActivity = millis();
	return _client->write(data);
}

size_t PubSubClient::write(const uint8_t *buffer, size_t size)
{
	lastOutActivity = millis();
	return _client->write(buffer, size);
}

size_t PubSubClient::buildHeader(uint8_t header, uint8_t *buf, uint16_t length)
{
	uint8_t lenBuf[4];
	uint8_t llen = 0;
	uint8_t digit;
	uint8_t pos = 0;
	uint16_t len = length;
	do
	{
		digit = len % 128;
		len = len / 128;
		if (len > 0)
		{
			digit |= 0x80;
		}
		lenBuf[pos++] = digit;
		llen++;
	} while (len > 0);

	buf[4 - llen] = header;
	for (int i = 0; i < llen; i++)
	{
		buf[MQTT_MAX_HEADER_SIZE - llen + i] = lenBuf[i];
	}
	return llen + 1; // Full header size is variable length bit plus the 1-byte fixed header
}

boolean PubSubClient::write(uint8_t header, uint8_t *buf, uint16_t length)
{
	uint16_t rc;
	uint8_t hlen = buildHeader(header, buf, length);

#ifdef MQTT_MAX_TRANSFER_SIZE
	uint8_t *writeBuf = buf + (MQTT_MAX_HEADER_SIZE - hlen);
	uint16_t bytesRemaining = length + hlen; //Match the length type
	uint8_t bytesToWrite;
	boolean result = true;
	while ((bytesRemaining > 0) && result)
	{
		bytesToWrite = (bytesRemaining > MQTT_MAX_TRANSFER_SIZE) ? MQTT_MAX_TRANSFER_SIZE : bytesRemaining;
		rc = _client->write(writeBuf, bytesToWrite);
		result = (rc == bytesToWrite);
		bytesRemaining -= rc;
		writeBuf += rc;
	}
	return result;
#else
	rc = _client->write(buf + (MQTT_MAX_HEADER_SIZE - hlen), length + hlen);
	lastOutActivity = millis();
	return (rc == hlen + length);
#endif
}

boolean PubSubClient::subscribe(const char *topic)
{
	return subscribe(topic, 0);
}

boolean PubSubClient::subscribe(const char *topic, uint8_t qos)
{
	if (qos > 1)
	{
		return false;
	}
	if (MQTT_MAX_PACKET_SIZE < 9 + strlen(topic))
	{
		// Too long
		return false;
	}
	if (connected())
	{
		// Leave room in the buffer for header and variable length field
		uint16_t length = MQTT_MAX_HEADER_SIZE;
		nextMsgId++;
		if (nextMsgId == 0)
		{
			nextMsgId = 1;
		}
		buffer[length++] = (nextMsgId >> 8);
		buffer[length++] = (nextMsgId & 0xFF);
		length = writeString((char *)topic, buffer, length);
		buffer[length++] = qos;
		return write(MQTTSUBSCRIBE | MQTTQOS1, buffer, length - MQTT_MAX_HEADER_SIZE);
	}
	return false;
}

boolean PubSubClient::unsubscribe(const char *topic)
{
	if (MQTT_MAX_PACKET_SIZE < 9 + strlen(topic))
	{
		// Too long
		return false;
	}
	if (connected())
	{
		uint16_t length = MQTT_MAX_HEADER_SIZE;
		nextMsgId++;
		if (nextMsgId == 0)
		{
			nextMsgId = 1;
		}
		buffer[length++] = (nextMsgId >> 8);
		buffer[length++] = (nextMsgId & 0xFF);
		length = writeString(topic, buffer, length);
		return write(MQTTUNSUBSCRIBE | MQTTQOS1, buffer, length - MQTT_MAX_HEADER_SIZE);
	}
	return false;
}

void PubSubClient::disconnect()
{
	buffer[0] = MQTTDISCONNECT;
	buffer[1] = 0;
	_client->write(buffer, 2);
	_state = MQTT_DISCONNECTED;
	_client->flush();
	_client->stop();
	lastInActivity = lastOutActivity = millis();
}

uint16_t PubSubClient::writeString(const char *string, uint8_t *buf, uint16_t pos)
{
	const char *idp = string;
	uint16_t i = 0;
	pos += 2;
	while (*idp)
	{
		buf[pos++] = *idp++;
		i++;
	}
	buf[pos - i - 2] = (i >> 8);
	buf[pos - i - 1] = (i & 0xFF);
	return pos;
}

boolean PubSubClient::connected()
{
	boolean rc;
	if (_client == NULL)
	{
		rc = false;
	}
	else
	{
		rc = (int)_client->connected();
		if (!rc)
		{
			if (this->_state == MQTT_CONNECTED)
			{
				this->_state = MQTT_CONNECTION_LOST;
				_client->flush();
				_client->stop();
			}
		}
	}
	return rc;
}

PubSubClient &PubSubClient::setServer(uint8_t *ip, uint16_t port)
{
	IPAddress addr(ip[0], ip[1], ip[2], ip[3]);
	return setServer(addr, port);
}

PubSubClient &PubSubClient::setServer(IPAddress ip, uint16_t port)
{
	this->ip = ip;
	this->port = port;
	this->domain = NULL;
	return *this;
}

PubSubClient &PubSubClient::setServer(const char *domain, uint16_t port)
{
	this->domain = domain;
	this->port = port;
	return *this;
}

PubSubClient &PubSubClient::setCallback(MQTT_CALLBACK_SIGNATURE)
{
	this->callback = callback;
	return *this;
}

PubSubClient &PubSubClient::setClient(Client &client)
{
	this->_client = &client;
	return *this;
}

PubSubClient &PubSubClient::setStream(Stream &stream)
{
	this->stream = &stream;
	return *this;
}

int PubSubClient::state()
{
	return this->_state;
}
